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|
--- lam.environment
local util = require "util"
local types = require("types")
if not table.unpack then table.unpack = unpack end
local global = {
-- constants
["#t"] = true,
["#f"] = false,
}
--- Types ---
for name, func in pairs(types) do
if name == "lamtype" then
global.type = func
else
global[name] = func
end
end
--- Basic functions ---
global.begin = function(...)
local xs = {...}
return xs[#xs]
end
global.car = util.car
global.cdr = util.cdr
global.list = function(...) return {...} end
--- Higher-order functions ---
global.apply = function(fn, ...)
local args = {...}
local last = args[#args]
assert(types.luatype(last) == "table", "Bad apply")
table.remove(args)
for _, v in ipairs(last) do
table.insert(args, v)
end
return fn(table.unpack(args))
end
global.map = function(fn, list)
return util.map(fn, list)
end
--- Math ---
-- NOTE: we do not have the full numeric tower yet!
for name, func in pairs(math) do
global[name] = func
end
global["+"] = function (...)
return util.reduce({...}, 0, function (a, b) return a + b end)
end
global["-"] = function (...)
local args = {...}
if #args == 0 then
error("Too few arguments: need at least 1")
elseif #args == 1 then
return (-args[1])
else
local result = args[1]
for v = 2, #args do
result = result - args[v]
end
return result
end
end
global["*"] = function (...)
local result = 1
for _, v in ipairs({...}) do
if v == 0 then return 0 end
result = result * v
end
return result
end
global["/"] = function (...)
local args = {...}
if #args == 0 then
error("Too few arguments: need at least 1")
elseif #args == 1 then
if args[1] == 0 then error("Division by zero") end
return (1/args[1])
else
local result = args[1]
for v = 2, #args do
if args[v] == 0 then error("Division by zero") end
result = result / args[v]
end
return result
end
end
global["="] = function (...)
for _, v in ipairs({...}) do
if not a == b then return false end
end
return true
end
global["<"] = function (...)
for _, v in ipairs({...}) do
if not a < b then return false end
end
return true
end
global["<="] = function (...)
for _, v in ipairs({...}) do
if not a <= b then return false end
end
return true
end
global[">"] = function (...)
for _, v in ipairs({...}) do
if not a > b then return false end
end
return true
end
global[">="] = function (...)
for _, v in ipairs({...}) do
if not a >= b then return false end
end
return true
end
---
return global
|
